BJ 74 Transfer case/transmission seal replacement.... (1 Viewer)

Joined
Aug 24, 2016
Messages
38
Location
Smithers, BC
I installed an OME 2.5' lift and got the well documented slight "grinding" sound on deceleration. It only occurs in 4 wheel drive, so is something in the front end. It is louder when the hubs are not locked. My local mechanic took a hard look and replaced one of the u-joints, and tightened up the nut on the front transfer output shaft. But it didn't fix the noise. Further investigation found oil leaking from the auto transmission to the transfer case, so it appears the seal is gone. There is no apparent play in the bearing on the front output shaft. The drive shaft was not removed, so is not "out of phase" or other potential issues.

So, we likely need to replace the transmission/transfer case seal to address the leak. And its possible the front output shaft bearing is contributing to the noise (not sure though). He has looked at the service manual and is looking for more info on how to replace that seal between transmission and transfer case. He's a great mechanic but not familiar with these split case units.

Is it best to remove the transmission and transfer case to get at the seal, or to pull apart the transfer case while on the truck? Is there any detailed description on how to get at the seal? Its not super clear in the manual and the posts I've seen don't really cover that seal. Pics would be amazing....

And.....while he's in there, is it best to just rebuild everything (bearings, seals) or just the parts that appear worn? It sounds to me like the labor of getting the TC apart is the biggest part of the job.

FWIW, the truck has 157,000 km and otherwise in good shape.

Any info is appreciated.
 

FJBen

SILVER Star
Joined
Apr 1, 2004
Messages
5,352
Location
Northern Colorado
I just rebuilt my t-case a little over a month ago. I had a decent front output shaft leak that started about 1 month before the rebuild. This whole process you have here sounds almost identical to mine other than my lift has been on for a really long time.

#1: leaking started happening at front output shaft and got pretty bad quickly. I replaced the front seal but noticed that the front output shaft felt a little notchy when turning it. Pretty much knew at that point a rebuild was coming.

#2 the noise on decel in 4wd. I only got this right before I rebuilt the t-case. Had to drive in a blizzard and it was noisy.

#3 I rebuilt the t-case using @orangefj45 kit and video to rebuild. I rebuilt mine while it was still on the truck. Had I known 2 weeks later I would be dropping the H55F/tcase to fix an input shaft on the H55f, I would have just pulled it all and rebuilt the tcase on the bench, however it wasn't that hard at all on the truck.

#4 My front driveshaft is pretty worn on the slip-shaft. On the truck you can grab right at the slip and move it, more than normal which causes noises. Usually a noise on decel after a lift is ujoints. I plan on just buying a complete new front driveshaft from Toyota as it's actually cheaper than getting mine rebuilt with new ujoints and slip joint.

My theory on why the slip joints/front u-joints wear weird is because they have either spent a hell of a lot of time in 4WD, or none at all. With none at all, everything just kind of sits and rubs/wears in one spot for miles and miles causing flat spots and wear outs. Then when you lift it, everything is now rubbing/moving at different spots. I chose to put new ujoints in the rear driveshaft when I did the t-case rebuild.

If I were you, I would just rebuild the whole t-case/gaskets/bearings while you are in there. You have to tear it basically all the way down anyways to get to that seal. My seal was hard/brittle and explained why my tranny/tcase were sharing fluid.
 
Joined
Aug 24, 2016
Messages
38
Location
Smithers, BC
I just rebuilt my t-case a little over a month ago. I had a decent front output shaft leak that started about 1 month before the rebuild. This whole process you have here sounds almost identical to mine other than my lift has been on for a really long time.

#1: leaking started happening at front output shaft and got pretty bad quickly. I replaced the front seal but noticed that the front output shaft felt a little notchy when turning it. Pretty much knew at that point a rebuild was coming.

#2 the noise on decel in 4wd. I only got this right before I rebuilt the t-case. Had to drive in a blizzard and it was noisy.

#3 I rebuilt the t-case using @orangefj45 kit and video to rebuild. I rebuilt mine while it was still on the truck. Had I known 2 weeks later I would be dropping the H55F/tcase to fix an input shaft on the H55f, I would have just pulled it all and rebuilt the tcase on the bench, however it wasn't that hard at all on the truck.

#4 My front driveshaft is pretty worn on the slip-shaft. On the truck you can grab right at the slip and move it, more than normal which causes noises. Usually a noise on decel after a lift is ujoints. I plan on just buying a complete new front driveshaft from Toyota as it's actually cheaper than getting mine rebuilt with new ujoints and slip joint.

My theory on why the slip joints/front u-joints wear weird is because they have either spent a hell of a lot of time in 4WD, or none at all. With none at all, everything just kind of sits and rubs/wears in one spot for miles and miles causing flat spots and wear outs. Then when you lift it, everything is now rubbing/moving at different spots. I chose to put new ujoints in the rear driveshaft when I did the t-case rebuild.

If I were you, I would just rebuild the whole t-case/gaskets/bearings while you are in there. You have to tear it basically all the way down anyways to get to that seal. My seal was hard/brittle and explained why my tranny/tcase were sharing fluid.
Thanks. great info.
 
Joined
May 21, 2006
Messages
437
Location
Rotoiti, New Zealand
Pro tip if you do it on the truck: superglue the layshaft rear thrust washer in place for re-assembly. The manual says stick it on with grease but that doesn't work well.

When I rebuilt mine I took the entire t-case/trans out to work on as we had a lift & trans. jack. Once you have everything off the t-case there's not much more work to take the whole mess out & it's definitely easier to work on standing on end.

157K is not really much for one of these but as as the service kit is pretty cheap compared to the work of getting in there I'd agree with Ben & say do the lot.

Cheers
Clint
 

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